1. Field of the Invention
The present invention relates generally to a heat exchanger for an automotive vehicle. More particularly, the present invention relates to a method for manufacturing a plate for a plate-tube type evaporator.
2. Disclosure Information
Plate-tube heat exchangers are well known in the art. In these types of heat exchangers, a plurality of elongated plates are joined together, such as through a lamination process to define a plurality of passageways for the movement of a fluid therethrough. Each of the passageways is formed by the inwardly facing surfaces of a pair of joined plates. The interior surfaces of the joined plates generally define a central fluid conducting section. The passageways are interconnected so that a fluid may flow through the plurality of joined plates forming the heat exchanger. As is also known in the art, conductive fin strips are located between outwardly facing surfaces of the pairs of joined plates. Heat exchangers of this type have particular utility as evaporators for air conditioning systems of motor vehicles, and one such heat exchanger is described in U.S. Pat. No. 5,125,453, assigned to the assignees of the present application.
Typically, the plates used in heat exchangers such as described in the '453 patent are formed by stamping or pressing the plate configuration from a sheet of deformable material, such as steel or aluminum. As shown in the '453 patent, the plates include a plurality of beads which act to disrupt the flow of fluid between pairs of plates. The beads are formed in a single drawing process, wherein each of the beads are formed in one operation. Although adequate in most applications, it has been determined that drawing the beads in a single operation can cause microcracking around the sharp corners of the beads. These cracks result in leakage of the plates and ultimately in reduced effectiveness of the heat exchanger. Therefore, it would be desirable to form the plates so that cracking at the beads does not occur.
It is an advantage of the present invention to provide a method of making the heat exchanger plates to reduce cracking and leakage around the beads.